I don't recall the source but I had heard an interesting theory of a biological basis for pedophilia... basically, most of us (with "healthy" sexual attractions) have some sort of filter going on in our brains that identifies family members, children and other people who we shouldn't be sexually attracted to, and shuts off our ability to be attracted to them. Non-attraction to children is not just something we choose... our bodies are actually programmed to make that decision for us. And then for some people, that filter is just not functional, so that even if it's rationally clear that it's wrong to act on those attractions,
This is an interesting idea, but you're really describing here a biological basis against pedophilia. One would think there would be built-in biological barriers against harming our own, or harming the vulnerable. The non-working filter idea doesn't sound true to me, though. We know incest, for example, is extremely common, from its most benign manifestations to its most abhorrent. That would have to be a lot of non-working filters. But if that's the case, it's an argument for acculturation and grooming overriding natural instincts, a notion that I think may apply to porn, especially het male porn.
A biological basis for pedophilia would suggest that at some point, or under some circumstances, it was biologically advantageous, but evidently not for long as it would in that case have become a dominant characteristic. But it's an interesting concept. Again, not to excuse it.
Thing is, I'm not sure there is a standard anymore for "healthy" sexual attractions in humans. In no way do I want to excuse abuse, exploitation or violence of any kind, but I think we tend to conform to what we agree is normal, and that's a social thing. Human sexual expression has proven to be far more diverse than we acknowledge. That's why I'm curious to what degree certain sexual expressions that we "healthy" folks find abhorrent have a biological basis and/or to what extent they are groomed and acculturated (if that's a word). We can certainly agree what's legal and what's socially acceptable, but how much can we really say to someone else "that's fucked up and you need help"? It would help us greatly if we could get to the bottom of some of these questions.